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Mass extinctions have wiped out the majority of life on Earth at least five times. About 66 million years ago, a mass extinction killed off the dinosaurs and three out of four species on Earth, the report said.

Though such extinctions are often associated with asteroids, the worst mass die-off around 252 million years ago, which wiped out 90 percent of life on Earth, was caused by methane spewing microbes, according to a new theory.

The microbes produced much the same effect as climate change — a sudden rise in temperatures and acidification of the oceans. Both phenomena can be observed today due to global warming, and man-made climate change was cited by the report as one factor making traditional habitats unlivable for many species.

Though scientists have been aware that mass extinctions are occurring, this study calculates the actual rate of extinction — not just the number of species disappearing — before and after humans appeared on the scene.

In 1995, Duke University’s Stuart Pimm of Duke University, the study’s lead author, calculated that before humans were on the scene, one out of 1 million species went extinct every year.

Today, the rate is between 100 to 1,000, according to Pimm, who also heads a conservation nonprofit called Saving Species.

That trend can be reversed if biologists can pinpoint where vulnerable species are, according to the study. Once they have that information, they can try to save the species by preserving their habitats.

Habitat loss is the number one factor in the accelerating rates of global extinction, the study said. Humans have developed and taken over too much land, and many species no longer have a place to live.

Pimm and co-author Clinton Jenkins of the Institute of Ecological Research in Brazil suggested that the increasing availability of smartphones and conservation apps could allow the public to help researchers find endangered animals

This online crowdsourcing of species distribution could expand online databases and could help scientists better identify and protect vulnerable species. That data can then be combined with information already available on changing land and ocean use to better identify and protect vulnerable species.